This skill uses extended thinking for complex architectural trade-off analysis. ultrathink

ADR Writer

Writes complete, validated Architecture Decision Records in MADR 4.0.0 format and commits them to docs/decisions/. Follow write-adr.prompt.md for the full 10-step workflow.

When to Activate

Activate on:

• "write an ADR for X"
• "create an ADR"
• "document this decision"
• "ADR for X"
• "architecture decision record for X"
• "record this decision"
• "document the decision to use X"
• "we decided to use X, write that up"
• Invoked from check-adr-violations.prompt.md with a supersedes: NNNN parameter

Do NOT activate on:

• "what ADR covers X?" → lookup task, read the index
• "show me the ADR for Y" → lookup task, read the file
• "does this violate an ADR?" → audit task, use check-adr-violations.prompt.md
• "check ADR compliance" → audit task, use check-adr-violations.prompt.md

MADR 4.0.0 - Mandatory Sections

Every ADR must contain all five mandatory sections. Missing any one = invalid.

Section	Required	Notes
YAML frontmatter	✅	status + date always present
Context and Problem Statement	✅	2–4 sentences, factual, project-specific
Considered Options	✅	2–4 options, concise noun phrases
Decision Outcome	✅	Must start with Chosen option: "X", because
Consequences	✅	At least one Good + one Bad bullet

Phrasing Rules (non-negotiable)

Decision Outcome - exact format:

Chosen option: "{option name}", because {justification}.

Consequences bullets - exact format:

- Good, because {positive consequence}.
- Bad, because {negative consequence}.
- Neutral, because {neutral consequence}.

Numbering Convention

1. Read docs/decisions/README.md - find highest NNNN
2. Increment by 1
3. Filename: NNNN-short-title.md (lowercase kebab-case, max 5 words)
4. Always update the index table in docs/decisions/README.md after writing the file

Status Values

Status	When to use
accepted	Decision is made and implemented (most common)
proposed	Decision under discussion, not yet implemented
superseded	Replaced by a newer ADR - add superseded-by: NNNN - Title
deprecated	No longer relevant, not replaced

Supersede Flow

When replacing an existing ADR (triggered by violation checker or user intent):

1. New ADR frontmatter gets supersedes: "NNNN - Old Title"
2. Old ADR frontmatter changes to status: superseded + superseded-by: "NNNN - New Title"
3. Old ADR row in docs/decisions/README.md status column → superseded
4. New ADR row added to index as accepted

Optional: Web Research

If the user asks for external evidence or benchmarks to support the decision, invoke the web-research-specialist agent before finalizing. Use its findings in the Consequences section or a More Information section.

Arguments

When invoked with the supersedes: NNNN argument (either by user or from check-adr-violations.prompt.md), the $ARGUMENTS variable contains the ADR number to supersede.

Example invocation: /adr-writer supersedes: 0005

The argument is parsed to:

• Mark the old ADR (0005) as status: superseded
• Add supersedes: "0005 - Old Title" to the new ADR frontmatter
• Update the index table in README.md to reflect the supersession

If no arguments are provided, this is a new ADR with no supersession relationship.

Session Tracking

This skill logs the session ID using ${CLAUDE_SESSION_ID} for correlation:

ADR creation session: ${CLAUDE_SESSION_ID}

This allows tracking which ADRs were written in the same conversation and correlating with git commits when troubleshooting.

Action

Invoke .github/prompts/write-adr.prompt.md and follow its steps in order. Do not shortcut or skip the validation step.